| 层结海洋中小振幅内行进波的演变和破碎 |
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| 引用本文： | 李丙瑞,田纪伟,范海梅,刘志亮,赵骞.层结海洋中小振幅内行进波的演变和破碎[J].地球物理学报,2006,49(2):360-366. |
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| 作者姓名： | 李丙瑞 田纪伟 范海梅 刘志亮 赵骞 |
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| 作者单位： | 1.中国海洋大学海洋环境学院物理海洋实验室，青岛 266003 2 国家海洋局第一海洋研究所海洋环境科学与数值模拟重点实验室，青岛 266061 3 中国科学院海洋研究所，青岛 266071 |
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| 基金项目： | 国家青年863项目（2004AA639830）资助. |
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| 摘 要： | 采用高精度的拟谱方法，数值模拟了层结海洋中小振幅内行进波的演变和破碎过程.在演变过程中，导致内波破碎的PSI不稳定机制在共振相互作用中逐渐占据主导地位，能量从初级波向低频、高波数运动缓慢传递并形成一次级波包，随即破碎发生.破碎后产生的层化湍流引起的强烈混合以及湍流间歇性可从总能量和涡度峰度随时间的变化趋势看出.我们分析了层化湍流的一些统计特性，包括动能和有效位能沿垂向波数ky的功率谱.结果表明，动能和有效位能谱都存在一个谱段满足k-3y律，且分别可表示为01N4k-3y和02N4k-3y(N为Brunt Visl频率)，通常称其为浮力子区.另外，我们分析了Cox数(湍流扩散系数与分子扩散系数之比)，在层化湍流维持在一定强度时，计算结果和由海洋内区观测(远离内波强生成源和复杂地形)所推测的结论较为吻合.
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| 关 键 词： | 内波破碎 拟谱方法 浮力子区 Cox数 |
| 文章编号： | 0001-5733（2006）02-0360-07 |
| 收稿时间： | 2005-01-24 |
| 修稿时间： | 2005-01-242005-09-12 |
Evolution and breaking of a propagating internal wave in stratified ocean |
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| LI Bing-Rui,TIAN Ji-Wei,FAN Hai-Mei,LIU Zhi-Liang,ZHAO Qian.Evolution and breaking of a propagating internal wave in stratified ocean[J].Chinese Journal of Geophysics,2006,49(2):360-366. |
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| Authors: | LI Bing-Rui TIAN Ji-Wei FAN Hai-Mei LIU Zhi-Liang ZHAO Qian |
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| Institution: | 1.Institute of Physical Oceanography, Ocean University of China, Qingdao 266003, China 2 Key Laboratory of Marine Science and Numerical Modeling, State Oceanic Administration, Qingdao 266061, China 3 Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China |
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| Abstract: | The processes of evolution and breaking of a propagating internal wave are directly numerically simulated using the pseudo spectral method. The mechanism of PSI (parametric subharmonic instability) involved in the evolution is testified clearly, which dominates gradually in nonlinear resonant interactions. As a consequence, the energy cascades to a second plant wave packet with low frequencies and higher wavenumbers with respect to the primary wave. With the growth of this wave packet, wave breaking occurs and causes strong nonlinear regime, i.e. stratified turbulence. The strong mixing and intermittent of the turbulence can be learned from the evolution of the total energy and kurtosis of vorticity vs. time. Some statistic properties of the stratified turbulence are analyzed, including the spectra of KE (kinetic energy) and APE(effective potential energy) along vertical wavenumber ky. The results show that these spectra display a wavenumber range scaling as 01N4k-3y and 02N4k-3y, respectively (N is the Brunt Visl frequency), which is called buoyancy sub range. The Cox number of diapycnal diffusivity is also calculated, and it shows a good consistency with the observations and deductions in ocean interiors during the stage of the stratified turbulence maintaining a fairly active level. |
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| Keywords: | Internal wave breaking Pseudo-spectral method Buoyancy sub-range Cox number |
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